Diseases affecting the nervous system are many, whereas effective treatments are few. Recent experimental successes with neural stem cells (NSCs) in rodent models therefore provide encouragement to those working to repair the brain, retina, and spinal cord. In our experience, as well as that of others, NSCs demonstrate an unprecedented capacity for integration into the diseased central nervous system (CNS) of mature mammals. Furthermore, it is now clear that multipotent neural precursors can be derived from post-natal sources, apparently including cadaveric human tissue. The recent development of transgenic mice expressing green fluorescent protein (GFP), either constitutively or under control of the nestin promoter (pNestin-EGFP), has enabled the derivation of NSCs pre-labeled with this marker. The studies proposed here will characterize constitutive and conditional GFP-expressing transgenic NSCs in terms of baseline production of cytokines, expression of a range of surface markers, regulatory control of surface marker expression in response to cytokine stimulation and immunogenic activity in mixed co-cultures.